The technique such as the vertical axis type wind power station or wind power plant has been well known in the art.
An example is disclosed in JP-A-10-110666. What is disclosed in JP-A-10-110666 is the straight-blade vertical axis (H-Darrieus) type wind-driven device, the blades of which are fixed at their two end portions by a pair of support members positioned in the vertical direction along the direction of the rotating post. For preventing the global warming or for rational use of energy, on the other hand, the wind-driven device has to be disposed at a higher position for a higher electric power thereby to increase the turning motions of the wind-driven device, as shown in FIG. 1, FIG. 2 and FIG. 7 of JP-A-10-110666. For this necessity, it is preferred that the wind-driven device is placed on the roof of a house or building (as will be generally called the “building”).
In another vertical axis type wind-driven device of the prior art, on the other hand, blades made of glass fibers are supported by two upper and lower arms of glass fibers, which are horizontally extended from an upright rotating post made of a hollow outer rotor of a metal, as disclosed in Japanese Patent No. 3,368,537. Moreover, this wind-driven device is a straight blade type, in which straight blades are arranged around the vertical axis and connected to the post side through support blades. Considering the efficiency, the self-startability and the noises, the wind-driven device is intended to optimize the solidity, the angle of attachment and the blade thickness.
As disclosed in JP-A-2003-56447, on the other hand, there is a power generating wind-driven device, in which the portions of the device attaching the blades are made movable to switch the direction and angle of the pitch automatically according to the wind direction so that the turning direction of the device may always be constant no matter whether the wind direction might be changed to positive/negative directions. In place of the windbreak forest, the power generating wind-driven devices are disposed long in parallel for the windbreak purpose, and the wind is utilized to turn the devices so that the turning forces are connected to construct the windbreak power generating plant for driving the power generator.
However, the wind-driven devices may make the turning motions of the blades unstable, because they cannot arrange the flows of wind around the blades. For raising the power generation efficiency of the wind, moreover, it is still necessary to improve the structure of the blades. Depending on the situation of the building, still moreover, the wind-driven device cannot be disposed on the roof of the building and may be arranged on a pole fixed in the ground. In this case, the wind-driven device is exposed to a strong force by a strong wind, and the pole supporting the wind-driven device has to be reliably fixed in the ground. Therefore, it is necessary to take a long time for disposing the wind-driven device such as for digging the ground deeply. This necessity may raise the cost for the disposition.
On the other hand, the power generating wind-driven device of Japanese Patent No. 3,368,537 cannot sufficiently suppress the bending moment caused by the centrifugal force either at the joint portions between the arms and the blades or at the central portions of the blades. At the high-speed turning time of the blades, the bending moment rises to such a high value as may break the blades. In order to suppress the bending moment, measures have to be taken by thickening the arms or by raising the strength of the blades, thereby to invite a large weight of the vertical axis type wind-driven device. Moreover, the rotating post is subjected, when it receives a cross wind, to an extremely high bending moment. This makes it necessary to thicken the rotating post considerably and to enlarge the diameter of the bearings of the rotating post accordingly. This necessity raises a problem that the device is too much enlarged to be used as the power generating device.
In the power generating wind-driven device of JP-A-2003-56447, the direction and angle of the pitch are automatically switched according to the wind direction by making movable the blade attaching portions of the wind-driven device. Therefore, the adjoining wind-driven devices may contact with each other unless they are arranged at a predetermined or more spacing. This has made it impossible to achieve the efficient windbreak effects.
An object of the present invention is to provide: a vertical axis type wind power station and a blade manufacturing process, which can stabilize the turning motions of blades and can raise the power generation efficiency; a structure and method for mounting the wind-driven device of a wind power station, by which the wind-driven device can be easily disposed at the upper portion of a building; and a windbreak wind power plant for breaking the wind by using the wind power devices.